We made a high-quality GPU renderer GPUGI which focuses on baking lightmaps with global illumination effects, e.g., multi-bounce indirect lighting, environment lighting, ambient occlusion, soft shadows, etc. By exploiting the GPU's streaming architecture through all stages of lighting, GPUGI achieves a very high performance: it can generate all lightmaps of a sponza-like scene in only a few seconds. GPUGI is applied to some published games, e.g. LUAN DOU XI YOU, TIAN XIA HD, TU JI YING XIONG 2015 and a series of unpublished games. This talk will cover a series of GPU technologies that we used in GPUGI, including per-model deferred shading, point cloud generation, octree building, k-near interpolation, lighting discontinuity reduction, memory optimization for large scale scenes, and some other optimization tricks.